It’s a really great first try. But they missed some key things that I think help a ballpark be unique.

Bullpens, barely any stadiums have foul line bullpens. I suggest making the bullpens a built in option. That dictates the wall configurations available to you. I understand cut away shots were probably complicated, but if you do a few options. You can have them as preset.
Wall material/back stop. Behind the plate views need to be more unique and have some advertisement boxes. What makes a person want to go to a ballpark is seeing it on TV. If behind the plate can’t be unique, does it really stand out. It doesn’t have to be a fish tank, but something. There should also be a function to change all the wall material. Some Limestone options or other materials, would really allow a unique view.
Foul territory, foul territories always define the field. Put in a few different field options and it will give a bunch of options.
Scoreboard and Different things on Walls, make the thin scoreboards available as a wall item like the Phillies or Pirates Stadiums. Make the signs available to put on the walls. Logos of Teams or Field names.
Active Areas. This I get is difficult. But if I design a concession area, I’d like to see some people in it
Are there night games? It always seems to be day time in games in the create a stadiums. Don’t tell me how amazing the shadows are and they don’t move with the time of day.
Dugout. No screens on dugouts, and not different type of dugouts.

Snapping outfield field level seats should be able to clip against walls.

It’s a really great first try and I hope they put some updates into some updates,